AN attempt will be made to identify the active transport of an ion responsible for the pump in the corneal endothelium by simultaneously measuring the flux of water and two ions, as well as the electrical potential across the layer. Particular attention will be paid to the transport of HCO3, and CO2, which will be separated by means of pH changes in the medium. Endothelial layers will be grown in tissue culture and it will be seen if it can be induced to show active pumping in this state. The use of cultured endothelial cells as donor material will be pursued and the conditions promoting endothelial cell proliferation will be studied. The factors responsible for the ingrowth of blood vessels into the cornea will be investigated. The mechanism of excitation of corneal nerves will be examined. Whether temperature and touch are mediated through the same nerve endings will be re-examined in an isolated corneal preparation. The nerve-excitation mechanism will be studied by searching for synergistic action between stimuli.